Field of the Invention
The present invention relates to a dust cover for a ball joint.
Further, the present invention relates to a dust cover for a ball joint which is used in an automobile suspension device, and a steering device.
Description of the Conventional Art
Conventionally, as a ball joint to which a dust cover is installed for the purpose of a dust prevention and a water prevention in a ball joint coupling portion, there has been known a dust cover for a ball joint which is described in FIG. 7.
Since this kind of dust cover 800 for a ball joint is of a type that an inner peripheral surface of a one-end large-diameter opening portion 500 is fitted to an outer peripheral surface of a socket, film portions 700 are not in contact with each other as shown in FIG. 8 even if the dust covers 800 are laminated.
However, in a dust cover 800 of a type that an outer periphery of a one-end large-diameter opening portion 500 is fitted to an inner peripheral surface of a socket, as shown in FIG. 9, film portions 700 thereof are in contact with each other in the case that the dust covers 800 are laminated. As shown in FIG. 10.
As a result, there has been brought about a problem that the film portions 700 are stuck to each other, whereby not only it takes a lot of trouble with a peeling work but also the film portions 700 are damaged, if the state mentioned above is left for a long time due to a conveying work.
Consequently, there has been proposed a countermeasure for avoiding the contact between the film portions 700 by forming a plurality of outer peripheral projections 910 on an outer peripheral surface of the film portion 700 of the dust cover 800 as shown in FIG. 11.
In the case of laminating correctly, it is possible to avoid the contact between the film portions 700 as shown in FIG. 12, however, there has been brought about a problem that the dust covers 800 are deviated as shown in FIG. 13 and the film portions 700 are in contact with each other due to vibration during the conveyance and failing at the laminating time.